What a flush casement costs in 2026
A flush casement is a hinged window where the opening sash closes flush with the frame, sitting level with its face rather than standing slightly proud as a standard stormproof casement does. The result is a clean, even line that echoes traditional timber joinery, which is why it suits period homes, conservation areas and modern builds wanting a crisp finish. That precision comes at a price: a uPVC flush casement runs roughly £300 to £800 fully fitted in 2026 by size, with a typical mid-size window around £500. The calculator above does not have a separate Flush style, so select the standard Casement style and add the flush premium using the size table below.
Because the flush look is the whole point, it is worth comparing it directly against the standard option before you commit. The casement window calculator prices the standard stormproof version, and the master double glazing costs page sets casement pricing against the other styles.
| Flush casement (uPVC) | Low | High | Average |
|---|---|---|---|
| 600 x 900 mm | £300 | £400 | £350 |
| 1,200 x 1,200 mm | £450 | £550 | £500 |
| 940 x 1,600 mm | £470 | £570 | £520 |
Source: Checkatrade 2026 (How Much Are uPVC Flush Casement Windows in 2026). Flush units carry roughly a 30% premium over a standard casement; aluminium and timber rise further.
Is the flush premium worth it
The honest answer depends on where the window goes. On a front elevation, a period cottage or anywhere in a conservation area, the flush face is a genuine upgrade that looks far closer to original timber, and the roughly 30% premium is money well spent. On a plain rear elevation where nobody studies the windows, a standard casement does the same job for less. If your home is a period property, weigh this against a true timber option in the timber window calculator, or compare a vertical-sliding sash if that suits the age of the house better.
The verdict on flush casements
A flush casement is the best uPVC choice where appearance matters, giving a near-timber look without timber upkeep. Where looks are secondary, the standard casement is the value pick.
Worth it Flush casements: worth it on front elevations, period homes and conservation areas; standard casement elsewhere.
I fit a lot of flush casements on cottages and barn conversions because they look the part without the maintenance of timber. They do cost more, and on the back of the house I often talk customers back down to a standard casement. Spend the flush premium where people actually see it.
Tom Bradley, FENSA-registered installer
Frequently asked questions
A uPVC flush casement costs roughly £300 to £800 fully fitted in 2026 depending on size, with a typical mid-size window around £500. A full set for a 3-bed home (about 12 windows) comes to roughly £7,500.
A flush casement sits flat within the frame when closed rather than overlapping it, which needs tighter tolerances and more precise joinery. That extra accuracy is why flush units are the premium option, with some sources putting the uplift at around 30% over a standard stormproof casement.
On a standard stormproof casement the opening sash sits slightly proud of the frame. On a flush casement the sash closes flush with the frame for a clean, even face, which mimics traditional timber joinery. The flush look suits period homes and modern designs alike.
For period properties, conservation areas and homeowners who want the cleanest finish, yes. For a plain rear elevation where appearance matters less, a standard casement does the same job for less, so it is worth pricing both.